1. Field of the Invention
The present invention relates to an Organic Light Emitting Device (OLED), and more particularly, the present invention relates to a white OLED having stabilized colors and improved light emitting efficiency.
2. Description of the Related Art
Organic Light Emitting Devices (OLEDs) are light emitting devices that use a phenomenon whereby light is generated by combining an electron and a hole in an organic light emitting layer when a current or voltage is supplied in the organic light emitting layer. In order to obtain a better light emitting property, an OLED may have a multi-layer structure in which a Hole Injection Layer (HIL) and a Hole Transporting Layer (HTL) are formed between an anode electrode and the organic light emitting layer and an Electron Injection Layer (EIL) and an Electron Transporting Layer (ETL) are formed between a cathode electrode and the organic light emitting layer.
The driving voltage of the OLED is approximately 5 V so that low voltage driving of the OLED is possible. Also, surface emitting with high brightness, quick response speed, and a thinner OLED are realizable. In addition to this, color reproduction is excellent, wide viewing angles are available, and emitted colors can be easily changed by appropriate selection of fluorescent materials. Accordingly, OLEDs can be used in various fields, such as full color display devices, backlight units for Liquid Crystal Displays (LCDs), information display devices, vehicle display devices, and lighting devices.
The white OLED emits white light and has a structure in which light emitting layers of predetermined colors are stacked therein. Such a white OLED can be applied to, in particular, a paper-thin light source, a backlight unit for an LCD, and full color display devices employing a color filter. However, since the materials forming the light emitting layers of each color are different in the white OLED, if a current injected into the white OLED is changed, stable colors cannot be realized. In addition, light is generated from the light emitting layers of each color in the white OLED so that the light emitting efficiency of the white LCD is lower than that of the OLED including a light emitting layer of a single color.